1. Field of the Invention
The instant disclosure relates to a computing device and an automatic controlling method thereto, more particularly to the computing device with imaging function and its auto-focusing method for projection.
2. Description of Related Art
Projector is one of the image output facilities often seen in the office or any meeting room. Some of the large projectors may conduct active focus adjustment according to the result made by an inside sensing element, therefore an auto-focusing is performed. The mentioned sensing element may be implemented to be an infrared sensor, a sonar sensor, or the like. The projector may use the sensing element to acquire the distance between the projector and the projecting screen. After that, the position where the projection lens of the projector projects on may be positioned. It is noted that the size of the projector may be too big to be a part of portable computing device since the volume occupied by the sensing element may not be reduced. The portable computing device may be a notebook computer or a personal digital assistant.
There is the small-scale projecting device existed on the market for projecting image as connecting to a computing device. However, in order to minimize the size, no sensing element is disposed to measure the distance and without the capability of auto-focusing. Therefore, a user would have to manually adjust the focusing distance of the projection lens based on the user's experience.